[flow] enable enforce_local_inference_annotations (#25921)

This setting is an incremental path to the next Flow version enforcing
type annotations on most functions (except some inline callbacks).

Used
```
node_modules/.bin/flow codemod annotate-functions-and-classes --write .
```
to add a majority of the types with some hand cleanup when for large
inferred objects that should just be `Fiber` or weird constructs
including `any`.

Suppressed the remaining issues.

Builds on #25918

Author: kassens

packages/jest-react/src/internalAct.js

@@ -122,7 +122,7 @@ export function act<T>(scope: () => Thenable<T> | T): Thenable<T> {
   }
 }
 
-function flushActWork(resolve, reject) {
+function flushActWork(resolve: () => void, reject: (error: any) => void) {
   if (Scheduler.unstable_hasPendingWork()) {
     try {
       Scheduler.unstable_flushUntilNextPaint();

packages/react-cache/src/ReactCacheOld.js

@@ -7,7 +7,7 @@
  * @flow
  */
 
-import type {Thenable} from 'shared/ReactTypes';
+import type {ReactContext, Thenable} from 'shared/ReactTypes';
 
 import * as React from 'react';
 
@@ -48,7 +48,7 @@ const ReactCurrentDispatcher =
   React.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED
     .ReactCurrentDispatcher;
 
-function readContext(Context) {
+function readContext(Context: ReactContext<mixed>) {
   const dispatcher = ReactCurrentDispatcher.current;
   if (dispatcher === null) {
     // This wasn't being minified but we're going to retire this package anyway.
@@ -62,6 +62,7 @@ function readContext(Context) {
   return dispatcher.readContext(Context);
 }
 
+// $FlowFixMe[missing-local-annot]
 function identityHashFn(input) {
   if (__DEV__) {
     if (
@@ -133,7 +134,7 @@ function accessResult<I, K, V>(
   }
 }
 
-function deleteEntry(resource, key) {
+function deleteEntry(resource: any, key: mixed) {
   const entriesForResource = entries.get(resource);
   if (entriesForResource !== undefined) {
     entriesForResource.delete(key);

packages/react-client/src/ReactFlightClient.js

@@ -94,6 +94,7 @@ type SomeChunk<T> =
   | InitializedChunk<T>
   | ErroredChunk<T>;
 
+// $FlowFixMe[missing-this-annot]
 function Chunk(status: any, value: any, reason: any, response: Response) {
   this.status = status;
   this.value = value;
@@ -104,6 +105,7 @@ function Chunk(status: any, value: any, reason: any, response: Response) {
 Chunk.prototype = (Object.create(Promise.prototype): any);
 // TODO: This doesn't return a new Promise chain unlike the real .then
 Chunk.prototype.then = function<T>(
+  this: SomeChunk<T>,
   resolve: (value: T) => mixed,
   reject: (reason: mixed) => mixed,
 ) {
@@ -369,7 +371,11 @@ export function reportGlobalError(response: Response, error: Error): void {
   });
 }
 
-function createElement(type, key, props): React$Element<any> {
+function createElement(
+  type: mixed,
+  key: mixed,
+  props: mixed,
+): React$Element<any> {
   const element: any = {
     // This tag allows us to uniquely identify this as a React Element
     $$typeof: REACT_ELEMENT_TYPE,
@@ -446,6 +452,7 @@ function createModelResolver<T>(
       value: null,
     };
   }
+  // $FlowFixMe[missing-local-annot]
   return value => {
     parentObject[key] = value;
     blocked.deps--;
@@ -465,7 +472,7 @@ function createModelResolver<T>(
 }
 
 function createModelReject<T>(chunk: SomeChunk<T>) {
-  return error => triggerErrorOnChunk(chunk, error);
+  return (error: mixed) => triggerErrorOnChunk(chunk, error);
 }
 
 export function parseModelString(

packages/react-client/src/ReactFlightClientStream.js

@@ -122,6 +122,7 @@ export function processBinaryChunk(
 }
 
 function createFromJSONCallback(response: Response) {
+  // $FlowFixMe[missing-this-annot]
   return function(key: string, value: JSONValue) {
     if (typeof value === 'string') {
       // We can't use .bind here because we need the "this" value.

packages/react-debug-tools/src/ReactDebugHooks.js

@@ -350,7 +350,7 @@ const Dispatcher: DispatcherType = {
 // create a proxy to throw a custom error
 // in case future versions of React adds more hooks
 const DispatcherProxyHandler = {
-  get(target, prop) {
+  get(target: DispatcherType, prop: string) {
     if (target.hasOwnProperty(prop)) {
       return target[prop];
     }
@@ -404,7 +404,7 @@ export type HooksTree = Array<HooksNode>;
 
 let mostLikelyAncestorIndex = 0;
 
-function findSharedIndex(hookStack, rootStack, rootIndex) {
+function findSharedIndex(hookStack: any, rootStack: any, rootIndex: number) {
   const source = rootStack[rootIndex].source;
   hookSearch: for (let i = 0; i < hookStack.length; i++) {
     if (hookStack[i].source === source) {
@@ -425,7 +425,7 @@ function findSharedIndex(hookStack, rootStack, rootIndex) {
   return -1;
 }
 
-function findCommonAncestorIndex(rootStack, hookStack) {
+function findCommonAncestorIndex(rootStack: any, hookStack: any) {
   let rootIndex = findSharedIndex(
     hookStack,
     rootStack,
@@ -446,7 +446,7 @@ function findCommonAncestorIndex(rootStack, hookStack) {
   return -1;
 }
 
-function isReactWrapper(functionName, primitiveName) {
+function isReactWrapper(functionName: any, primitiveName: string) {
   if (!functionName) {
     return false;
   }
@@ -460,7 +460,7 @@ function isReactWrapper(functionName, primitiveName) {
   );
 }
 
-function findPrimitiveIndex(hookStack, hook) {
+function findPrimitiveIndex(hookStack: any, hook: HookLogEntry) {
   const stackCache = getPrimitiveStackCache();
   const primitiveStack = stackCache.get(hook.primitive);
   if (primitiveStack === undefined) {
@@ -488,7 +488,7 @@ function findPrimitiveIndex(hookStack, hook) {
   return -1;
 }
 
-function parseTrimmedStack(rootStack, hook) {
+function parseTrimmedStack(rootStack: any, hook: HookLogEntry) {
   // Get the stack trace between the primitive hook function and
   // the root function call. I.e. the stack frames of custom hooks.
   const hookStack = ErrorStackParser.parse(hook.stackError);
@@ -520,8 +520,8 @@ function parseCustomHookName(functionName: void | string): string {
 }
 
 function buildTree(
-  rootStack,
-  readHookLog,
+  rootStack: any,
+  readHookLog: Array<HookLogEntry>,
   includeHooksSource: boolean,
 ): HooksTree {
   const rootChildren = [];
@@ -764,7 +764,7 @@ function inspectHooksOfForwardRef<Props, Ref>(
   return buildTree(rootStack, readHookLog, includeHooksSource);
 }
 
-function resolveDefaultProps(Component, baseProps) {
+function resolveDefaultProps(Component: any, baseProps: any) {
   if (Component && Component.defaultProps) {
     // Resolve default props. Taken from ReactElement
     const props = assign({}, baseProps);

packages/react-devtools-core/src/backend.js

@@ -44,7 +44,7 @@ const hook: ?DevToolsHook = window.__REACT_DEVTOOLS_GLOBAL_HOOK__;
 
 let savedComponentFilters: Array<ComponentFilter> = getDefaultComponentFilters();
 
-function debug(methodName: string, ...args) {
+function debug(methodName: string, ...args: Array<mixed>) {
   if (__DEBUG__) {
     console.log(
       `%c[core/backend] %c${methodName}`,
@@ -276,7 +276,7 @@ export function connectToDevTools(options: ?ConnectOptions) {
     scheduleRetry();
   }
 
-  function handleMessage(event) {
+  function handleMessage(event: MessageEvent) {
     let data;
     try {
       if (typeof event.data === 'string') {

packages/react-devtools-core/src/standalone.js

@@ -86,11 +86,12 @@ let bridge: FrontendBridge | null = null;
 let store: Store | null = null;
 let root = null;
 
-const log = (...args) => console.log('[React DevTools]', ...args);
-log.warn = (...args) => console.warn('[React DevTools]', ...args);
-log.error = (...args) => console.error('[React DevTools]', ...args);
+const log = (...args: Array<mixed>) => console.log('[React DevTools]', ...args);
+log.warn = (...args: Array<mixed>) => console.warn('[React DevTools]', ...args);
+log.error = (...args: Array<mixed>) =>
+  console.error('[React DevTools]', ...args);
 
-function debug(methodName: string, ...args) {
+function debug(methodName: string, ...args: Array<mixed>) {
   if (__DEBUG__) {
     console.log(
       `%c[core/standalone] %c${methodName}`,
@@ -166,6 +167,7 @@ function onDisconnected() {
   disconnectedCallback();
 }
 
+// $FlowFixMe[missing-local-annot]
 function onError({code, message}) {
   safeUnmount();
 

packages/react-devtools-extensions/src/backend.js

@@ -8,6 +8,7 @@
 
 let welcomeHasInitialized = false;
 
+// $FlowFixMe[missing-local-annot]
 function welcome(event) {
   if (
     event.source !== window ||
@@ -42,7 +43,7 @@ function welcome(event) {
 
 window.addEventListener('message', welcome);
 
-function setup(hook) {
+function setup(hook: any) {
   if (hook == null) {
     // DevTools didn't get injected into this page (maybe b'c of the contentType).
     return;
@@ -55,6 +56,7 @@ function setup(hook) {
 
   const bridge = new Bridge({
     listen(fn) {
+      // $FlowFixMe[missing-local-annot]
       const listener = event => {
         if (
           event.source !== window ||

packages/react-devtools-inline/src/backend.js

@@ -10,6 +10,7 @@ import type {BackendBridge} from 'react-devtools-shared/src/bridge';
 import type {Wall} from 'react-devtools-shared/src/types';
 
 function startActivation(contentWindow: any, bridge: BackendBridge) {
+  // $FlowFixMe[missing-local-annot]
   const onSavedPreferences = data => {
     // This is the only message we're listening for,
     // so it's safe to cleanup after we've received it.
@@ -96,6 +97,7 @@ export function createBridge(contentWindow: any, wall?: Wall): BackendBridge {
   if (wall == null) {
     wall = {
       listen(fn) {
+        // $FlowFixMe[missing-local-annot]
         const onMessage = ({data}) => {
           fn(data);
         };

packages/react-devtools-inline/src/frontend.js

@@ -37,6 +37,7 @@ export function createBridge(contentWindow: any, wall?: Wall): FrontendBridge {
   if (wall == null) {
     wall = {
       listen(fn) {
+        // $FlowFixMe[missing-local-annot]
         const onMessage = ({data}) => {
           fn(data);
         };